1. Field of the Invention
The present invention relates to workholding apparatuses and, more particularly, is directed to apparatuses for supporting multiple vise-like workholding devices in predetermined orientations on a support surface such as a machine tool table or tooling plate.
2. Description of the Invention Background
Today, most modern machine shops are typically equipped with one or more computer numerically controlled ("CNC") machining apparatuses which can perform very precise machining operations on "workpiece(s)" at very high speeds. However, because such CNC machining devices typically cost several thousands of dollars and require a substantial economic investment to support their operation, it is desirable to keep that equipment operating as close to one hundred percent of the time as possible. The time that a CNC machining device remains idle while workpieces are being handled or manipulated to other machining orientations represents a loss in efficiency of use of the machine and, ultimately, a loss in the profitability of the workpieces or an increase in their cost.
A single CNC machine can generally perform a variety of different "machining" operations on a workpiece. For example, a CNC milling machine can be utilized for many machining operations including producing flat ends on workpieces, producing planar surfaces on workpieces, and drilling, tapping, and reaming holes in workpieces. A typical CNC milling machine is equipped with a vertically or horizontally mounted spindle that has a toolholder attached thereto. The toolholder is constructed to operably receive and support a tool therein which may comprise an end mill for producing flat ends, a flycutter for producing planar surfaces, a drill for drilling holes, a tap for producing threaded holes or a reamer for sizing holes to very precise dimensions.
Such milling machines are equipped with a milling table that is adapted to support workpieces or workpiece-supporting apparatuses commonly known as "workholders" thereon. A milling table is typically coupled to the milling machine by means including computer-controlled positioning devices. The table and/or spindle can be moved relative to one another very precisely along "x", "y" and "z" axes. Such relative movement defines a cubical area known as the "machining envelope" in which the milling machine is capable of performing various machining operations therein. As such, to maximize the machine's production, it is desirable to support as many workpieces as possible in machining orientations within the machine's machining envelope to reduce the amount of machine downtime encountered when replacing or reorienting workpieces within the machining envelope.
To achieve very accurate workpiece dimensions, the workpiece(s) must be supported within the machining envelope in very precise location(s) that are recognized by the computer. The workpiece(s) may be supported within the machining envelope by tool fixtures or clamps that are attached to the milling table or they may be supported in vise-like workholders such as the ones disclosed in U.S. Pat. No. 4,928,937 to Bernstein, U.S. Pat. No. 4,898,371 to Mills et al., U.S. Pat. No. 4,569,509 to Good, and U.S. Pat. No. 4,098,500 to Lenz. As can be gleaned from review of those patents, such vise-like workholders are adapted to clamp a single workpiece between opposing jaw members operably supported on a base that is adapted to be clamped or attached by other known locating and attachment methods to the milling table.
Depending upon the size(s) of the workpiece(s) to be machined, a plurality of such "single-station" vise-like workholders can be attached to the milling table or to a "tooling plate" adapted to be attached to the workholding table. Such workholders, however, due to their limited ability to secure numerous workpieces within the machining envelope (1) do not serve to maximize the use of a machine's machining envelope and, (2) thus, increase the amount of machine downtime. Moreover, such workholders typically only serve to present workpieces in a single machining orientation to the machine's spindle.
For most multiple-workpiece machining operations, viselike workholders, that are each capable of holding two or more workpieces in side-by-side orientations, are more desirable than the workholders described above. Examples of such "two-station" workholders are disclosed in U.S. Pat. No. 5,098,073 to Lenz, U.S. Pat. No. 5,022,636 to Swann, U.S. Pat. No. 4,934,674 to Bernstein, and U.S. Pat. No. 4,529,183 to Krason et al. Such workholders typically comprise a base that has a central jaw fixed thereto. Two outer jaws are operably supported on the base and can be selectively positioned relative to the fixed central jaw by a vise screw that is operably received in a longitudinal slot provided in the base. Again, however, those workholders do not make full use of the machine's machining envelope and, in most cases, can only present the workpieces in a single machining orientation.
Another workholding device of the type disclosed in U.S. Pat. No. 4,413,818 to Lenz, comprises a vise that has a base that operably supports two vise-like jaws on one side thereof. The remaining three sides of the base are configured for attachment to the machine tool table. While this vise or a plurality of such vises can be used to clamp workpiece(s) in essentially three different machining orientations, such vises fail to make substantial use of the machining envelope in the vertical direction because they must be attached to the milling table or a tooling plate attached to the milling table.
Another workholding device is disclosed in U.S. Pat. No. 2,535,450 to O'Malley. This device has two pairs of workholding jaws oriented at ninety degrees to each other. Thus, this workholding device can simultaneously support at least two workpieces in two different machining orientations relative to the milling table. While such workholding device makes further use of the machining envelope, it still does not maximize the use of the machining envelope, especially in the "Z" direction.
U.S. Pat. No. 5,094,436 to Stephan, III discloses a two stage machine vise, a plurality of which can be mounted to a common vertical support member that has an upper base and a lower base attached thereto. The lower base is adapted for attachment to the milling table or tooling plate that is attached to the milling table. This patent also teaches that this assembly of machine vises can be supported in a horizontal orientation. Such arrangements of workholders serve to further maximize the utilization of the machining envelope.
Perhaps, however, the vise-like workholders manufactured by Chick Machine Tool, Inc. of 800 Commonwealth Drive, Warrendale, Pa. 15086 under the trademarks "Multi-Lok", "Quick-Lok", and "Bi-Lok", serve to better utilize the machining envelope by providing a plurality of vise-like jaws operably configured on a common column member. The "Quick-Lok" and "Bi-Lok" vise-like workholders are "two-station" workholders that have a base with a fixed central jaw attached thereto. Two outer jaws are operably supported on the base and can be selectively positioned relative to the fixed central jaw by a vise screw that is operably received in a longitudinal slot provided in the base. The bases of those workholders can be attached directly to the milling table or tooling plate or they can be attached to a common support member designed to orient the workholders in predetermined orientations relative to the machine tool table or tooling plate.
The "Multi-Lok" workholders produced by Chick Machine Tool, Inc. are also two stage workholders that comprise a vise-like clamping assembly that is equipped with first and second movable jaw supports to which first and second jaw members may be removably attached. The clamping assembly is configured to be operably received on a single base having a longitudinal slot sized to slidably receive the clamping assembly therein. A central jaw is fixed to the base such that it is oriented between the first and second jaws to create a two-station workholder. Multiple clamping assemblies may be received in corresponding slots in a common column member to provide a cluster of workholders. Such column member can be vertically supported on a milling table such that the longitudinal axes of the clamping assemblies are substantially perpendicular to the milling table or other support surface or they can be rotatably supported on a selectively indexable support apparatus. However, to attach such columns to a support surface that is essentially parallel to the axes of the clamping assemblies in the column, the column must have a surface that is specially configured for attachment to the support surface. Thus while such column is well adapted to support a plurality of vise-like clamping assemblies on a milling table or tooling plate such that the axes thereof are substantially parallel to the milling table or tooling plate, when it is desirable to use that same column to support the clamping assemblies such that the axes thereof are substantially perpendicular to the milling table or tooling plate, the side of the column used to attach to the milling table in the horizontal orientation typically cannot be equipped with its own clamping assembly.
Thus, there is a need for an apparatus that can support a standard column with multiple vise-like clamping assemblies operably supported thereon on a tooling plate such that the axes of the clamping assemblies are substantially parallel to the tooling plate's support surface without sacrificing the column's ability to operably support a maximum number of slide assemblies when the column is mounted such that the slide axes are substantially perpendicular to the support surface.